Jet propulsion device for operation through fluid medium and method of operating it



Feb. 4, 1958 F. zwlcKY 2,821,838

JET PROPULSION DEVICE FOR OPERATION THROUGH FLUID MEDIUM AND METHOD 0FOPERATING IT med Apnlzs, 194s 4 sheets-sheet 1 v, m :L W m WZ M m A H MW F. zwlcKY 2,821,838 EVICE FOR OPERATION THROUGH AND METHOD OFOPERATING IT 4 Sheets-Sheet 2 A INVENTOR. FR/TZ ZW//(Y TTR/VEYS JETPROPULSION FLUID MEDIUM -.llllllllllllllll .DEDEN-HUUB..

Feb. 4, 1958 Filed April 28, 1945 E? o mm o Feb. 4, 1958 F. zwlcKYDEVICE FOR OPERATION THROUGH ANDv METHOD OF OPERATING IT JET PROPULSIONFLUID MEDIUM Filed April 28, 1945 4 Sheets-,Sheet 3 rTY iff" l "l A 7'1054/5 YJ' Feb. 4, ,1958 2,821,838

F. ZWICKY JET PROPULSION DEVICE FOR OPERATION THROUGH FLUID MEDIUM ANDMETHODl OF OPERATING IT Filed April 28, 1945 4 Sheets-Sheet 4 INVENTOR.FQ/ rz Z w/cL/.y

United States Patent O JET PROPULsIoN DEVICE FOR OPERATION THROUGH FLUIDMEDIUM AND METHOD OE OPERATING I T Fritz Zwicky, Pasadena, Calif.,assignor, by mesne asslgnments, to Aerojet-General Corporation,Cincinnati, h10, a corporation of Ohio Application April 28, 1945,Serial No. 590,833 18 Claims. .(Cl. 60-35.6)

This invention relates to propulsion devices of the type adapted topropel crafts, planes or the like through a uid medium, and moreparticularly to jet propulsion means and methods.

The principal object of this invention is to improve the operatingperformance and eticiency of such devices.

In my copending application, Serial No. 558,219, filed October l1, 1944,Ihave disclosed and claimed a jet propelled device, adapted to be driventhrough an air medium in the form of an elongated duct or channel havingan entrance at the front through which the fluid from the medium mayenter and an exhaust nozzle at the rear through which it may exit. Inthe operation of that device, fuel is burned within the duct, and theheat of combustion thereby generated is transmitted to the mass of airentering the duct. The air and combustion products are forced throughthe exhaust nozzle at a high velocity and the reaction thereby createdproduces the propulsive force.

In the apparatus described in my said copending appli-` cation the gasesand heat are formed by the combustion of a fuel-air mixture which is redin the combustion chamber at either atmospheric pressure or the pressurebuilt up in the system above atmospheric, by its structuralv mannerconverts a greater proportion of the available thermal energy from thefuel into useful work than would otherwise be obtained from explodingthe same amount of fuel without compression.

I provide the desired precompression of the regular or main fuel chargeby exploding somewhere in the region of the main fuel mixture apreliminary charge which precedes the main explosion of the regular fuelmixture thereby placing it under pressure. The effect is advantageouslyprocured by exploding such a preliminary charge in a chamber withinwhich the regular charge is to be burned. The preliminary charge can beone which burns at a lower temperature or pressure, or both, than theregular charge; and the increased temperature or pressure, or both,caused by the explosion of the preliminary charge may be employed toignite the regular charge. A preferred feature of my invention is thetiring of a preliminary explosive charge in such a manner that the mainexplosive charge is subjected to pressure from both ends of the maintiring chamber.A The compressive preliminary explosion'may also becreated, for example, by the use of substances which spontaneously'explode whenv contacted with air, or, which may be catalyticallyexploded in air. tired by some suitable means such as av spark plug orhot spot if necessary. Thistype of an explosionv in which each explosion4of amain charge is preceded by apreliminary explosion is hereafterreferred to asa .cascading explosion.

The compressed charge may also bev vided with-'a curvature as shownI inFigs. 6--and"7 The v explosive mixture which is more easily ignited oroxidized than the main fuel charge.

The foregoing and other features of my invention will be betterunderstood by the detailed description and the accompanying drawings inwhich:

Fig. 1 is a longitudinal cross section view showing the device in whichthis invention is employed;

Fig. 2 is a cross section view taken on the line 2-2 of Fig. 1 showingthe fuel injectors and firing plugs used in an apparatus employing thisinvention;

Fig. 3 is an enlarged cross section view of the ring chamber and centraltiring tube shown in Fig. 1;

Fig. 4 is a'broken detail view of the front elevation of the valveassembly in the valve housing;

Fig. 5 is a perspective view of one of the blades;

Fig. 6 is a perspective view partly in cross section showing the valveblades interleaved between two valve members;

Fig. 7 is a perspective view looking up from beneath one of the channelmembers;

Fig. 8 is a perspective view showing one of the channel blades for usein twochannels simultaneously;

Fig. 9 is a broken view in cross section showing an alternativecascading tiring chamber equipped to handle substances spontaneouslydecomposable in air;

Fig. 10 is a broken view in cross section showing van` alternative formof cascading tiring chamber adapted to handle catalytically decomposedsubstances;

Fig. ll is a broken view in cross section showing an alternative form ofcascading firing chamber;

Fig. 12 is a cross section view taken on line 12-12 of Fig. 11, showingthe nozzle plate;

Fig. 12a shows a detail taken in cross-section at line' Fig. 13 is abroken view partly in cross section showing another embodiment of acascading firing chamber; and

Fig. 14 is a graph showing the effect of cascadingcompared to the singleexplosion operation.

The device illustrated in Figs. 1 to 3 comprises a shell 1 forming aduct or passageway through which air is adapted to flow, the airentering at the mouth 7 and leaving at the exhaust nozzle 12. The shell1 comprises a leading section 2 which is preferably circular for aboutone-third of its length from the entrance 7 and then undergoes atransition to correspond to the rectangular outline ofV centersection`3. A square spacer frame 17 iits be` Sections 2, 3 and 4 arebolted together by a series of bolts i 5 and 6. Tail section 4 isprovided'with `a series of radiation ns 8 to insure cooling of the unit.

A valve assembly 36, for controlling the iiow` of the tluid through theduct, is located near the forward end of the channel and divides theduct into a forward portion and a rear portion. The construction ofblade valve assembly 36 is described in detail with reference to Figs.4, 5, 'and 7. This valve is built up of an assembly of alternatingflexible blades 72 and rigid channel members 71. Each rigid channelmember 71 comprises agree tangular-shaped plate 74 the upper face ofwhich is pro- Patented Fels.l 4, 1958 lower surfaceofkplate 74 isprovided with a number of I channelsv77 formed by channel members 80which are integral with the plate and run parallel with each other asshown. These channel partitions 80 taper in depth being deeper at theleading edge 79 and tapering at the rear edge 83 to coincide withthethickness of the rear edge' of the blade. The uppersurface of members71 is provided with a series of parallel ridges `84 corresponding with anumber of channels and are positioned so as to be centered withreference to each' respective channel.

In 'assembling the valve assembly 36 several liexible blades" 72 arealternately"interleaved between several channel members 71 and arefrmlyheld'near their leading edge' 73 between the channel strips 80 of onechannel member and the front flat face- 82 of the next."`These valvesand rigid channel members are vfurtherl held together bya series ofbolts 85 which pass through the holes 75 and 75a drilled in the bladesand channel members. When'a series of ythese valves and channel membersare installed to form the'cornple'ted valve assembly 36 theycompletely'occupy the'rectangular space inthe region preceding theringchamber 140. Forpurpose of assembly thesevalves slide'int amachined'rectangular area 10 cut 'in the front endof firing' chamberinsert section 9 and are held in placeat the lrearv by shoulder 16 andin front by spacer 17. The arrangement of"thes`e` valves in the valvereceiver'is shownin Figsi l, 4, 9, 10, 11 and 13. Y

Fig. 6 shows a perspective view illustrating one of the flexible blades72 sandwiched between two adjacent chan' nel members 71.`

Fig. `7 is `a view from the underneath 'side of 'channel' member 71kand` shows a portion of the blade valve in! cludngblade'72l Thecurvature of the face 74 offeach channel memberis such that the rearedge 83' of'each 3 channel comes down to meet the rear edge 78 of thecorresponding adjacentvalve blades 72 as more clearly shown in Fig. '6.-The arrangement is such that the lower edge'81 of all the l1channelpartitions 80 of each channel member is hat against the at surfaceofblade 72 as illustrated in Fig. 7.` By this assembly arrangement therear edges 78 of the flexible blades 72 are enabledl to vibrate so as toalternately contact and move away from the rear edges of 83 of members71. This creates the valve action as the valveis closed when blades 72'are tight against the channel members of valve body 71.

There is located within shell "1 a combustion chamber 40 which isheldiin place by'vane's 31 which are attached to insert section 9 andtofiring'char'nbert) by any suitable means such as welding;y Insertsfe'ction 9 is rectangularly shaped and slides into'therecessed section39 cut in the center section 3. Thei`nse rt` 9v isfelarnp'ed intoposition v against sho'ulder118 when' section 2 dand`spacer 17 arebolted to section 3. The ring'chamber' 40l is cylindrical in shape andis provided with fuel injectorsV 43. yInjector i 43 is preferably aspray nozzle'typfe of injector' capable of introducing the fuel as afine sprgayor mist.

A cylindrical tube 20`fof rsmaller diameter than-,the

main ring chamber 40' is heldgin position withinl firing chamber 40by aseries of supportin g`l eg s 2 1 fastened to the small tube and thefiring chamber 40 by any suitable means such as welding. The leading end22 of vthe ytube 20 is slightly flared makingthe tube slightly 'largerAin diameter at this point than throughoutthe rest of xits length. Tube20 is equipped with a fuel injector 2 3 located near the forward orflared end 22 ofthe tube. A

sparking device, 24 is prsvidedin the. tube, Tube 20. is shoterin lengththan the main tiring Chamber 40.v This.` is done to provide aregionuateither end of small v tube where the effects of theexplosion within they u lbe'can act upon the main explosive charge in ring chamber 40.

.Fd ndr..prssu,re. for.. @sample gasoline, is Yintro-. duced. into the`main iringhmber .40. thr0uehconduits 25 whic`h feed injectors 43. A morereactive orexplosive 4 material is lfired in the smaller tube. Itisintroduced into that region through conduits 26 and injector 23.

The way in which the apparatus operates is as follows: Tube 20 ischarged with a more easily explodable fuel than ring chamber 40. Forexample, if the fuel supplied to chamebr 40 is gasoline, the fuelsupplied to tube 20 may beoxygenand hydrogen, propane, butane, pentanefor otherlight hydrocarbons. 'The more stable 4fuel is supplied to firingchamber 40 simultaneously with the fuel supplied to the smaller tiringtube 20. The charge lin tube 20 is ldetonated and the force of theexplosion creates regions of pressure at' both ends of thering chamber40. This operation places the charge in 40 under pressure. Whenthischarge has been compresed a sucient degree and the temperature has beenraised to the proper point the charge lin chamber 40 will automaticallyexplode. The force of the explosion will cause valve 36 to shutl olfthej flow of' air enteringthrough mouth' 7 and will permit products ofcombustion to escape out ofboth ends of firing chamber 40. Part of the'products of combustion pass directly toward the rear andtheremainderissue from the front of'firing chamber 40 and then escapetoward the rear throughthe outer duct 38.` As soon as the pressuregenerated by the explosion diminishes to the -point where it is exceededby the pressure acting on the forward side ofthe' valve 36 the valvewill again open and permit free flow of 'air throughout the entireduct.' As soon as the valve opens to permit scavenging of the productsof the prior explosion of a new charge 'of fuel is admitted into thecombustion chamber which when mixed with the air forms a new explosivecharge. Likewise, a new charge of the more easily explodable mixture isintroduced into the smaller ring chamber within the large ring chamber40. The'smaller charge Ais exploded and the entire process of combustionrepeated. The operation consists of a series of these double explosionsrapidly following each other in such a manner that asubstantiallycontinuous thrust is produced.

Considering for a moment one 'of these double 'or cascaded explosions,the effect of the preliminary explosion' in the tube 20 upon the powerto be derived from the ultimate explosion in chamber 40 is clearlyillustrated inthe graph shown in Fig. 14 in'which the pressure devel--oped by the Vcascadingof the explosions is shown com'- pared to theeffect of a single explosion. The graph Shows a/plot of time'ag'ainstpressure. The pressure' reached at the end of the initial detonatio'n isshown by P and the resulting pressure developed after the explosion ofthe second, or more difficultly ignitable material in tube 40 isindicated at point'Pc. The graph taken during the operation of thedeviceshows' clearly the gain in pressure and Work which 'aremade'available when my invention is employed.

A modication yof the arrangement of Fig. l which may be used forproducing a similarv result is illustrated in Fig. 9. The apparatus'partly shown in Fig. 9 is similar to that in Fig." l except' that thefiring chamber insert 9 of Fig.'1 is replaced by a firing chambersection insert 19.

This section possessessimilar features to the one shown in Figjl withthe exception that the valve adjoins the tiring chamber.

'.In apparatuses of the type employing the firing chamberl adjoiningthevalve `as shown in Figs. 9, 10,'11, and l3-'iall`valve blades whichcome in contact with the circular area of firing'chamber are cut asshown in Fig. 8 by suitableslots 76to permit various portions of thevalve blade to act'in-depende'ntly. The distance between these slotswill'vary according to the portion of the firing i geniesse:`

the firing chamber to operate'independentlyfofsthat portion-f of thesame blade which opens into the duct'38. Proregion of the chamber hasbeen filled to the desired extent with the combustible mixture byinjectors 43. When the substance entering through injectors 61 comes incontact with sucient air it explodes and this explosion compresses thecharge in the forward portion of the chamber. The forward charge maythen either be ignited by spark plug 41 or may be exploded automaticallywhen the pressure and temperature are elevated to the proper degree.Substances which are suitable for spontaneous decomposition in air arealuminum borohydrides, boron hydrides such as B2H5, trimethylborine,aluminum trimethyl and zinc diethyl.

Another alternative which may be substituted for the firing chamberassembly of Fig. 1 is shown in Fig. 10 and a substance which iscatalytically decomposable in air is employed in place of a substancewhich is automatically decomposable in air. A catalyst bed 62 isprovided at some convenient position such as the nose portion of adeector 46 to support the catalytic bed 62. This catalytic bed performsthe function of initiating the decomposition of the substance.Propellant substances of this class are, for example, nitromethane andnitroparatiin. The catalyst may be platinum sheet or manganese dioxidemixed with other suitable metal oxides to increase its strength.Conduits 60 are installed in the rear of the firing chamber and throughnozzles 60a spray catalytically decomposable substances against the bed.This assembly is otherwise similar to the first alternative shown inFig. 9. Spark plugs 41 may be provided in the forward portion of thefiring chamber of Fig. to make certain that the decomposition orignition of the heavier fuel-air mixture Ytakes place.

Another embodiment of my invention is shown in Fig. 11. This apparatusmay be substituted for tiring chamber insert 9 used in Fig. 1. Thisfiring chamber insert 19b comprises forward firing chamber 100 adjacentto valve bank 36 and a rear firing chamber 101. Chambers 100 and 101 areheld in a central position by vanes 31. Firing chambers 100 and 101 areseparated bya nozzle plate 102 shown in Figs. 1l and 12. Nozzle plate102 is secured in the proper position to the walls of the firing chamberby any suitablemeans such as welding. Nozzle plate 102 is equipped witha plurality of small nozzles 106, preferably ofthe De Laval type. One ofthe nozzles is shown in cross-section in Fig. 12a. These nozzles 106 arearranged in such a manner that the axis of each nozzle is parallel tothe longitudinal axis of the firing chamber and perpendicular to thecross sectional area of the plate. The nozzles are preferably uniformlydistributed over the plate area so as to insure equal conduction betweenthe firing chambers 100 and 101. The opening 107 at the forward end ofnozzle 106 is larger in diameter than the discharge end 108. A fuelmixture such as hydrogen and oxygen, or pentane and air, which is morereadily ignited than the main fuel used in the propulsion of theapparatus, is introduced into chamber 101`through injector nozzle 104.At the same time the main fuel-air charge is introduced into firingchamber 100 through injector 103. The mixture in chamber 101 is flashedby any suitable means such as a spark plug 105. The pressure and theheat generated by the explosion in chamber 101 acts upon the lessreadily ignitable fuel-air mixture in chamber 100 and places the mixtureunder pressure, and the' heat generated by the explosion in chamber 101also is partly transmitted into the chamber 100.' When this pressure andtemperature are suflciently high to ignite the mixture in lchamber 100,the -fuel-air 6 products ofcoxnbustion/ndnthe heat toward the rearthrough the nozzle plate 102 and into the incoming mass of airwhich isentering through duct 38 which surrounds firing chamber A and 101. Withsome types ofl fuels it mayl be necessary to use suitable ignition meanssuch` as a spark` plug 109 or a hot spot located in the forward end ofthe tiring chamber100. The air passing over the firing chamber throughthefduct 38 is warmed by 'the radiation ofheat given olf by the firingchamber after each explosion has occurred. ln this manner the airwhichis mixed with the products of combustion has already. gainedadditional energy and velocity.

Another formof apparatus which is suitable to carry outlm'y inventionrisillustrated in Fig. 13. In this apparatus the `firing chamber insert 19ereplaces insert 9A holding the firing chamber of Fig. `1`. This insertsection comprises acentral firing chamber held in position by vanes 117.Firing chamber 110 is provided with three sets of injectors 111, 112,and 113 which have firing plugs 114, v11S4 and 116 located rearwardly ofeach set of injectors. t

Fuels which'are readily ignitible by spark plugs or hot spots areintroduced into the firing chamber by nozzles 111 and 113 and at thesame time a fuel which requires more pressure and heat to cause itsspontaneous decomposition is introduced through nozzle 112. Spark plugs114` and 116 lire the charge which has been introduced through injector111 and 113; The pressure waves created by the explosion of the easilyignitable substance at either -end of the tiring chamber travel towardthe center in such a way as to compress and heat the less easilyignitable fuel which is injected between them. Again this fuel underpressure may be set off by any suitable means such as spark plug 115' ormay be ignited when the temperature and pressure developed by thesimultaneous" explosion at each end of the firing chamber have raisedthe pressure and temperature of the main charge to a suicient degree tocause its spontaneous ignition. A similar procedure may be used with asingle tuel. This may `be injected through forward injector 111 andallowed to travel the length of the firing chamber. When the chamber isfilled the charge is flashed at both ends by plugs 114 and 116 therebycompressing the central portion of the fuel before it is fired.

I claim:

1. A reaction propelled device adapted for propulsion through aircomprising a duct having an inlet opening and an exhaust nozzle, a valveseparating the duct into a forward and rear portion, a combustionchamber located within the rear portion, an auxiliary combustion chamberof shorter length than the first-mentioned combustion chamber locatedwithin the first-mentioned combustion chamber, means for supplying acombustible charge to a forward portion and a rear portion, said valvebeing operable to admit air from the forward portion to the rear portionwhen the pressure in the forward portion exceeds that in the rearportion and to prevent any flow of gas from the rear portion to theforward portion when the pressure is greater in the rear portion than inthe forward portion, a main combustion chamber located within said rearportion, an auxiliary combustion chambervo shorter length than the maincombustion chamber 1ocated within the main combustion chamber, means forsupplying a combustible charge to the main combustion chamber and'meansfor supplying an explosive` charge `in i theauxiliarycombustionfchambenand means for-initiatingthe explosion of theexplosive charge -in the auxiliary combustionchamber. s n

Areacti'on propelled device adapted forfpropulsio'n throughaircomprising a duct having an inlet openingand an exhaust nozzle, a valveseparating theductl into a forwardV portion` and a rear portion, saidvalve being operable toadmitmainfrom the forward portion. to the rearportion, whenI the pressure invthe forward 'portion exceedspthat intherear portion and to prevent anyhow of gas Yfromtherearportion totheforward portion when theupressurehis greater in the rear portion'than'in the forward portion,l a combustion chamber inthe rear. portion,said combustionchamber being contiguous with said valve and of smallerjcross-section area than .thejinside' cross-,section area of the `part ofthe duct withinwhich it is located,r meansY for'introducing la.combustible charge ina region of said combustionuchamber, means forinmitair Vfrom the forward,portion to` the'rear portionl when thepressure in the forward portion exceeds that in therear portion and toprevent any` flow` of gas from the rear `portion Ito the forward portionwhen the pressureis greaterin the rear portion ,than in Athe forwardportion, a

combustion chamber in the 'rear portion, said combustion chamberhavingan opening which is Acontiguous with said valve end anotherlopening'away fromv said valve, and

being equipped with'means f or introducingja maincom" busptible chargein the centralregion' of the chamberand means at either side of saidcombustion region for in` trolucing an, explosive charge that maybe moreeasily ignited than the main'combustible charge, andmeans for initiatingsaidgeharges at .either side ofsaid central region. Y5. A reactionpropelled device adapted.for propulsion through air comprising a ducthavingan inlet opening and anlexhaust nozzle, a valve separating theduct into a for-` ward and rear portion, said valve being operable'toadmit air from the forward portion to the rear portion when thepressnrein theforward portion exceeds Lthat in thev rear portion and to;prevent Janyhow of gas from the 'rearlportion to the Aforward portionwhen the pressure is greater inthe rear portion than in the forwardportion, a .combustionochamber in therear portion, said combustionchamberhavingan opening which is contignous with said ValYe. .andanothet-.openingaway from the valve, means insaidcombustion harnber forintroducing a combus tihle charge in a region of thesaidcombustionchamber near the valve and Imeanswforl introducing aself-explosive substance capable of spontaneous ignition in air at `aregion f thegmhstipn chamber awavfrom the valve- 6. A reaction propelleddevice adapted for propulsion through air comprising a ducthavingan,inlet opening and anlexh'austy nozzle, av valve separating thejductinto a fory ward and rear portion, a combustion' ichamber in the rear Yportion, said combustionl char'nber""havingman openingwhich'iscontiguous'iwith saidvalve'and anHo'pfening v away y from thevalve, means for introducingfaniexplosive charge in 'a forward region`of the combustion chambenfmeans for introducinga substance'which isAeatalytically decomposed in air in a rear region of 'the chamber,catalytic means vfor initiating'the decomposition of the 'air explodablesubstances, saidrneans located inthe region where the catalyticexplodable -substance is introduced.

7. A reaction propelled device adapted forpropu'lsion through; aircomprising a duct having an inlet opening and" when the pressure in theforward' portion 'exceeds that ini' the rear portion and torpreventanyflow of gas from the rear portion to, the forward portion when vthepressureis greater in the rear portion than inthe forward portion,' amain tubular combustion4 chamber open 'at both ends' and 'locateddownstream from said valve and'of smaller` diameter than the ductthereby creating a ch'a'nnel'withiriA the duct and surrounding themaincombustion chamber, a second tubularcombustion chamber open at both endsand of shorterv length than the main tubular'chamber'and' located withinthe main combustion chamber, 'means'for supplying a combustible chargeto the main tubular combustionchamber, means f'or supplying anexplosivechargel into the second tubular combustion chamber, and' means forinitiating the explosion within the second combustion chamber.

8. A reactionpropelled device adapted for propulsion through air.comprising a duct'having an inlet opening' and an exhaust nozzle, avalve separating the duct into' a forward and rear portion, said'valvebeing operable to admitair from the forward' portion to the rearportion' when the pressure in the forward portion exceedsthat in therearportion and to prevent any flow of gas from the rear -portion to theforward portion when the pressure is greater in the rear portion than inthe forward portion, a mainV tubular `combustion chamber open at bothends and located downstream from said` valve, an inner tubularlcombustion chamber open at both ends and of shorter length than the'maintubular chamber located within the main combustion chamber, means forsupplying a com" bustible charge to the main tubular combustion chamber;means` for supplying an' explosive charge into the inner tubularcombustion chamber, ignition means to ignite the' explosivecharge'in theinnertubular combustion chamber, and ignition means'provided inthe maintubular com-- bustion chamber'to assist the decomposition of the maincombustible charge. n

9N. A reaction propelled device adapted for propulsion through aircomprising a duct having lan inlet opening and an vexhaust nozzle, avalve separating the duct'into a forward and rear portion, said valvebeing operable to admit air from the'forward portion to the rearportion' when the pressure in the forward portion exceeds that in therear portion and to prevent any ow of gas from the rear portion to theforward portion when the pressure is greaterl in the rear portion thanin the forward portion, a tubular combustion chamber locateddownstreamfrom said valve and of smaller diameter than the inner diameter of theductthereby providing a space for air to pass by the combustion chamber,said combustion chamber having an inner combustion chamber of shorterlength than the main combustion chamber, means for supplying acombustible charge to the main combustion chamber, means for supplyingan explosive charge to the inner combustion'chamberand means forinitiating the explosion in said'inner combustion chamber.

l0. A'method'of operating `a combustion motor having a combustionchamber, which comprises introducing a combustiblel charge: into `thecombustion vchamber and` introducing'amore easilydecomposable explosivecharge on either Sideiof Ithe main combustible charge, exploding themore readily cornbtistible'charges and promoting the explosion of thevmain combustible charge by employing pressure and'temperature created bythe explosion'of the more easily decomposable charges. l

l1. The methodf'of operatingan internal combustion motorl having a maincombustion chamber enveloping a smallerncombuistion chamberwhich opensinto themainj chamber, which "comprises introducing a combustible charge.in the main combustion chamber and introducing an explosive charge'inthesmaller combustion chamber, igniting the charge in said smallercombustion-chamber thereby creating pressure at the opening of thesmaller. combustion chamber and exploding the main combustible charge byemploying the pressure and temperature generated by the preliminaryexplosion.

Y 12. The method of operating a reaction propelled device having a maincombustion chamber with front and rear openings and surrounded by an airduct, said chamber enveloping a smaller combustion chamber of shorterlength than the main combustion chamber, comprising introducing acombustible charge in the main combustion chamber, introducing anexplosive charge into the smaller combustion chamber, igniting thecharge in said smaller combustion chamber and exploding the maincombustible charge in the main combustion chamber by the pressure andtemperature created by the explosion of the charge within the smallercombustion chamber, said explosion discharging the gases from the rearand front openings of said main combustion chamber in such a manner thatthe air 1n the region between the combustion chamber and the duct isheated and is forced toward the rear of the duct at increased velocityand temperature.

13. A reaction propelled device adapted for propulsion through aircomprising a duct having an inlet opening and an exhaust nozzle, a valvedividing the duct into a forward portion and a rear portion, a tubularcombustion chamber located within the rear portion, the longitudinalaxis of the tubular chamber being colinear with the axis of the duct,means for introducing a combustible charge in a region of said tubularcombustion chamber, means for introducing a second charge morecombustible than the first-mentioned charge, in another region of thechamber, and means for initiating the combustion of the secondcombustible charge, whereby the combustion of the second charge ignitesthe first-mentioned charge, thereby creating gases which are expelledthrough the exhaust nozzle.

14. A reaction propelled device adapted for propulsion through aircomprising a duct having an inlet opening and an exhaust nozzle, a valvedividing the duct into a forward portion and a rear portion, whereby airis adapted to enter the inlet opening, and pass through the valve whenthe valve is open, and flow out the exhaust nozzle, a combustion chamberlocated within the rear portion with a space between the combustionchamber and the inner Wall of the duct so that the air can readily ilowpast and around the combustion chamber, means for introducing acombustible charge in a region of said cornbustion chamber, means forintroducing a second combustible charge more combustible than thefirst-mentioned charge, in another region of the chamber, and means forinitiating the combustion of the second combustible charge, wherebycombustion of the second charge ignites the first-mentioned charge,thereby creating gases which are expelled with the air through theexhaust nozzle.

15. A device according to claim 14 in which the combustion chamber hasopenings at both ends thereof, one opening being located to face thevalve and the other opening being located to face the exhaust nozzle.

16. A reaction propelled device adapted for propulsion through aircomprising a duct having an inlet opening and an exhaust nozzle, a valvedividing the duct into a forward portion anJd a rear portion, a tubularcombustion chamber located within the rear portion, the longitudinalaxis of the tubular chamber being colinear with the axis of the duct, anauxiliary tubular chamber, the combustion chamber and the axis of theauxiliary chamber being colinear with the axis of the combustionchamber, means for introducing a combustible charge into the combustionchamber and means for introducing a second charge more combustible thanthe rst-mentioned charge in the auxiliary chamber and means forinitiating the combustion of the second combustible charge, whereby thecombustion of the second charge in the auxiliary chamber ignites thefirst-mentioned charge in the combustion chamber thereby creating gasesunder pressure which cause the gases to be expelled through the exhaustnozzle.

17. A reaction propelled device adapted for propulsion through air,comprising a Iduct having an inlet opening and an exhau'st nozzle, avalve dividing the duct into a forward portion and a rear portion, thevalve being constructed to open when the pressure in the forward portionis greater than in the rear portion and to close when the pressure inthe rear portion is greater than in the forward portion, a combustionchamber situated in the rear portion, and an auxiliary combustionchamber situated within the main combustion chamber, means forintro'ducing a combustible charge in the main combustion chamber andmeans for introducing a second combustible charge more combustible thanthe rst-mentioned charge in the auxiliary chamber, means for initiatingthe combustion of the second combustible charge whereby the combustionof the second charge ignites the rst-mentioned charge in the maincombustion chamber, thereby creating gases under pressure which closethe valve cau'sing the gases to be expelled through the exhaust nozzle.

18. A reaction propelled device adapted for propulsion through air,comprising a duct having an inlet opening and an exhaust nozzle, a valvedividing the duct into a forward portion and a rear portion and beingconstructed so that when the pressure is greater in the forward portionthan in the rear portion the valve is opened, and when the pressure isgreater in the rear portion than in the forward portion, the valvecloses, a tubular combustion chamber open at both ends and locatedwithin the rear portion so that it is coaxial with the longitudinal axisof the duct, one olf the openings being placed adjacent the valve, andthe other opening being directed toward the exhaust nozzle, injectionmeans for injecting a main combustible charge into the combustionchamber at a position near the valve, a second injection means forinjecting a second combustible charge more readily combustible than thefirst-mentioned charge at a position within the combustion chamber, moreremote from the valve than the first-mentioned injection means, meanswhereby ignition of the more readily combustible charge serves to ignitethe main combustible charge thereby producing gases under pressure whichoperate to close the valve causing the gases to be exhausted through theexhaust nozzle.

References Cited in the le of this patent UNITED STATES PATENTS 657,868Gobbe Sept. 11, 1900 1,021,521 Hroult Mar. 26, 1912 1,269,989 WilliamsJune 18, 1918 1,616,157 Werner Feb. 1, 1927 1,753,253 Tacchella Apr. 8,1930 1,947,375 Broderson Feb. 13, 1934 2,096,184 Lasley Oct. 19, 1937FOREIGN PATENTS 7,912 Great Britain Apr. 4, 1907

